HESI A2 Physics Quizlet

Correct Answer: D

Rationale: Surface tension is the result of cohesive forces between liquid molecules at the surface, creating a net inward force. When a small object floats on the liquid surface, the surface tension exerts a restoring force towards equilibrium, keeping the object stable. This force pulls the object back towards the liquid surface if it is displaced. This is why choice D, "Restoring force towards equilibrium," is the correct answer. Choices A, B, and C are incorrect. Buoyant force (A) acts on objects immersed in a fluid, not on objects floating on the surface. Pressure difference (B) would not cause sinking of a floating object. Drag force (C) is a resistance force that opposes motion, not related to surface tension in this context.

Correct Answer: C

Rationale: To calculate work, we use the formula Work = Force × Distance. In this scenario, Amanda exerts a force of 100 N to push the lawnmower a total distance of 20 rows × 30 meters/row = 600 meters. Therefore, the work done is 100 N × 600 m = 60,000 N⋅m. This is why choice C, 60,000 N⋅m, is correct. Choices A and B are incorrect as they do not accurately calculate the work done. Choice D is also incorrect as we can determine the work done using the provided information.

Correct Answer: B

Rationale: The correct answer is B: The speed of light. In Einstein's mass-energy equation (E=mc^2), 'c' represents the speed of light in a vacuum, which is approximately 3 x 10^8 meters per second. This constant is crucial in the equation as it shows the relationship between mass and energy. The speed of light is a fundamental physical constant and plays a significant role in various aspects of physics, including relativity. Incorrect choices: A: Distance in centimeters - Distance in centimeters is not represented by 'c' in Einstein's equation. C: Degrees Celsius - 'c' does not represent temperature in degrees Celsius in the equation. D: Centrifugal force - 'c' does not represent centrifugal force in the equation.

Correct Answer: B

Rationale: The correct answer is B: It is a unique point for each pure substance. The triple point is specific to each substance because it is determined by the unique combination of temperature and pressure at which all three phases can coexist. This is a fundamental property of the substance and remains constant regardless of the container size. Explanation of other choices: A: It can vary depending on the container size - This is incorrect as the triple point is a fixed characteristic of a substance and not influenced by the container size. C: The pressure at the triple point can be zero for some substances - This is incorrect as the triple point requires specific pressure and temperature conditions for all three phases to coexist. D: The temperature at the triple point can be above the boiling point of the liquid phase - This is incorrect as the triple point represents the temperature and pressure at which all three phases can coexist, which is below the boiling point.

Correct Answer: A

Rationale: The correct answer is A: Its energy is halved. Kinetic energy is calculated using the formula KE = 0.5 * mass * velocity^2. Since kinetic energy is directly proportional to the square of velocity, if the speed drops from 60 mph to 30 mph, the kinetic energy will be reduced by a factor of 4 (30^2/60^2), which means it is halved. Summary: B: Its energy is doubled - Incorrect. Decreasing the speed from 60 mph to 30 mph reduces the kinetic energy, not double it. C: Its energy is quadrupled - Incorrect. Decreasing the speed results in a decrease in kinetic energy, not quadrupling it. D: Its energy is divided by four - Incorrect. The kinetic energy is reduced by a factor of 4, not divided by four.